The invention relates to a method for transmitting data via a traction current conductor.
German patent 730 713 discloses a method for transmitting data via a traction current conductor with which drive current for rail vehicles can be simultaneously transmitted. In this method, the data can be transmitted between the rail vehicles and between a control center and the rail vehicles. Data is fed, as a data signal on a predefined frequency channel, into the traction current conductor using a transmitter device. The data signal is then transmitted via the traction current conductor to a receiver device and received there. The data signal is then evaluated during the acquisition of reception data corresponding to the data of the transmitter device. In the method described above, the data signal is fed at the rail vehicle end into the traction current conductor via a drive current collector, and received using said traction current conductor, arcs which occur between the traction current conductor and the drive current collector being capable of considerably disrupting the data transmission and, under certain circumstances, even interrupting it because the interference signal of the arc is superimposed on the data signal.
German patent 538 650 also discloses a method in which data is transmitted via a traction current conductor. In this method, data signals containing control commands are generated in a first locomotive and are fed into the traction current conductor for the purpose of the transmission of data to a second locomotive. The data information, that is to say the respective control command, is frequency coded here i.e. a data signal with a predefined frequency is assigned to each control command. The frequency is set in the method using a switching lever in the first locomotive. The data signals pass via the traction current conductor to a receiver device in the second locomotive in which they are received and evaluated.
In one embodiment of the invention, there is a method for transmitting data via a traction current conductor, which is simultaneously used to transmit a drive current to a vehicle which includes, for example, feeding, at a transmitter end, at least two data signals which each include the data, into the traction current conductor with different frequency channels, generating an arc occurring between the traction current conductor and a drive current collector of the vehicle, a frequency band of which is defined by the frequency channels being greater than the expected spectral bandwidth of an interference signal, transmitting the data signals via the traction current conductor to a receiver device and being received using by the receiver device and evaluating the data signals after the reception, during the acquisition of the reception data corresponding to the data of the transmitter device, wherein in the event of the interference signal occurring, the received data of the data signal whose frequency channels lie outside the spectrum of the interference signal defined by the spectral bandwidth is selected as the reception data.
In one aspect of the invention, the method for transmitting data via a traction current conductor includes, for example, adding check bits to the data at the transmitter end and determining in the receiver device whether the data transmitted with the respective data signals has been transmitted free of errors, and wherein the data signals which have been transmitted free of errors are treated as lying outside the spectrum of the interference signal.
In another aspect of the invention, the method for transmitting data via a traction current conductor includes, for example, feeding at least three data signals into the traction current conductor with different frequency channels, the frequency band including the frequency channels being at least twice as large as the spectral bandwidth of the interference signal, comparing the data items of the received data signals with one another at the receive end; and selecting the received data of the data signals which have a majority of identical data items to one another and are transmitted as the reception data.
In yet another aspect of the invention, the method for transmitting data via a traction current conductor includes, for example, selecting the received data of the data signals whose amplitude has not left a specific amplitude band during the time necessary for the transmission of a data signal as the reception data.
In still another aspect of the invention, the data signals are OFDM signals.
In one aspect of the invention, the method for transmitting data via a traction current conductor includes, for example, transferring the data to a fixed receiver device using a transmitter device of the vehicle.
In another aspect of the invention, the data is transferred to the vehicle using a fixed transmitter device.
In yet another aspect of the invention, the data is transferred to a fixed receiver device using a fixed transmitter device.
In still another aspect of the invention, the data is transferred from the vehicle to another vehicle.